Elastic Introducer Sheath

ABSTRACT

An elastic percutaneous elastic introducer sheath is disclosed which can locally expand and reduce to accommodate a transcatheter medical device. The elastic introducer sheath includes a non-circumferentially continuous elastic frame, a liner, and a jacket.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit under 35 U.S.C. 119(e) to U.S.Provisional Patent Application 61/719,360, filed Oct. 26, 2012, which isincorporated by reference herein in its entirety. This application isalso a continuation-in-part of U.S. Non-Provisional application Ser. No.13/791,110, filed Mar. 8, 2013, which is incorporated by referenceherein in its entirety.

BACKGROUND

1. Field of the Disclosure

The present disclosure is related to percutaneous introducer sheaths, inparticular an elastic percutaneous elastic introducer sheath designed tointroduce a transcatheter device into a patient's vasculature. Theelastic percutaneous elastic introducer sheath can accommodate thedelivery of transcatheter devices of a range of sizes.

2. Background Art

A percutaneous introducer sheath is used to access the vascular systemof a patient and acts as a way to introduce and position varioustranscatheter medical devices within the patient. The introducer sheathis a tube-like member which is partially inserted into the vasculatureat a puncture site, typically in either the femoral, brachial, or radialartery of the patient. The proximal, or working end, of the introducersheath is accessible outside of the vasculature for the introduction oftranscatheter medical devices through the sheath. A guide wire can beinserted through the introducer sheath and subsequently steered throughthe vascular system to the site of therapy.

A typical introducer sheath system contains an access lumen forintroduction of transcatheter medical devices, a Luer hub for connectionto syringes and other peripheral devices, and a hemostasis valve toprevent blood loss from the lumen of the introducer sheath.

Large-profile transcatheter medical devices have traditionally requireda larger-profile introducer sheath which provides a fixed internalclearance to allow the device to pass through the patient's vasculature.Such procedures using the large-profile transcatheter medical devices,typically through the femoral artery, are therefore limited to patientswith sufficient vessel size to accommodate the introducer sheath. Inorder to extend the availability of large-profile transcatheter devicesto patients with smaller vessel sizes, an introducer with a smallerprofile that locally expands within the patient's vasculature to allowpassage of the large-profile transcatheter device is desired. Localexpansion and subsequent recoil of the elastic introducer profile isless traumatic on the patient's vessel than a sustained expansion for alarge-profile introducer sheath.

BRIEF SUMMARY

Provided herein is an elastic percutaneous introducer sheath thatgenerally includes a liner, an elastic frame, and a jacket having alongitudinal gap. The elastic introducer can be locally expanded once insitu and can elastically recoil to a reduced diameter. The elastic framewithin the introducer allows expansion of the introducer, especiallywhen passing the largest part of the transcatheter medical device beingintroduced. By use of the elastic frame, only the part of the introducerwith the largest portion of the device is expanded. Once thetranscatheter device is passed, the elastic frame acts as a spring tofully or partially collapse the diameter of the introducer.

In view thereof, disclosed herein are aspects of a surgical accesssystem including an introducer having an interior lumen, the lumen beingconfigured to expand from a first diameter to a second diameter, theintroducer including an elastic frame and a diameter retention elementpositioned at a distal end of the introducer to retain the distal end ofthe introducer at the first diameter.

In another exemplary embodiment, disclosed herein are aspects of asurgical access system comprising an introducer having an elastic frameand an interior lumen, the lumen being configured to expand from a firstdiameter to a second diameter, and a dilator slidably disposed about theinterior lumen, the dilator including a distal tip having an outerdiameter greater than the first diameter, and a diameter retentionelement positioned at a proximal end of the tip to retain a distal endof the introducer at the first diameter.

In another exemplary embodiment, disclosed herein are aspects of asurgical access system including an introducer having an elastic frameand an interior lumen, the lumen being configured to expand from a firstdiameter to a second diameter, and a dilator slidably disposed about theinterior lumen, the dilator having a first portion having a first axialstiffness and a second portion distal to the first portion, the secondportion having a second axial stiffness such that the dilator isconfigured to bend at the second portion.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

The accompanying figures, which are incorporated herein, form part ofthe specification and illustrate embodiments of an elastic surgicalaccess device. Together with the description, the figures further serveto explain the principles of and to enable a person skilled in therelevant art(s) to make and use the elastic surgical access devicedescribed herein. In the drawings, like reference numbers indicateidentical or functionally similar elements.

FIG. 1 is a sectional view of an elastic introducer according to anaspect of this disclosure.

FIG. 2 is a front view of a wire structure of an elastic introduceraccording to an aspect of this disclosure.

FIG. 3 is a front view of a wire structure of an elastic introduceraccording to an aspect of this disclosure.

FIG. 4 is a front view of a wire structure of an elastic introduceraccording to an aspect of this disclosure.

FIG. 5 is a perspective view of a wire structure of an elasticintroducer according to an aspect of the disclosure.

FIG. 6 is a top view of a wire structure of an elastic introduceraccording to an aspect of this disclosure.

FIG. 7 is a perspective and cut away view of an elastic introduceraccording to an aspect of this disclosure.

FIG. 8 is a sectional view of an elastic introducer according to anaspect of this disclosure.

FIG. 9 is a sectional view of an elastic introducer according to anaspect of this disclosure.

FIG. 10 is a top view of an elastic introducer according to an aspect ofthis disclosure.

FIG. 11 is a top view of an elastic introducer according to an aspect ofthis disclosure.

FIG. 12 is a top view of an elastic introducer according to an aspect ofthis disclosure.

FIG. 13 is a top view of an elastic introducer according to an aspect ofthis disclosure.

FIG. 14 is a top view of an elastic introducer according to an aspect ofthis disclosure.

FIG. 15 is a top view of an introducer system according to an aspect ofthis disclosure.

FIG. 16 is a perspective view of a wire structure of an elasticintroducer according to an aspect of the disclosure.

FIG. 17 is a top view of an elastic introducer according to an aspect ofthis disclosure.

FIG. 18 is a sectional view of an elastic introducer according to anaspect of this disclosure.

FIG. 19 is a perspective and cut away view of an elastic introduceraccording to an aspect of this disclosure.

FIG. 20 is a perspective view of an elastic introducer frame accordingto an aspect of this disclosure.

FIG. 21 is a perspective view of an elastic introducer frame accordingto an aspect of this disclosure.

FIG. 22 is a perspective view of an elastic introducer frame accordingto an aspect of this disclosure.

FIG. 23 is a perspective view of an elastic introducer frame accordingto an aspect of this disclosure.

FIG. 24 is a perspective view of an elastic introducer frame accordingto an aspect of this disclosure.

FIG. 25 is a perspective view of an elastic introducer frame accordingto an aspect of this disclosure.

FIG. 26 is a side view of an elastic introducer frame projectionaccording to an aspect of this disclosure.

FIG. 27 is a front view of an elastic introducer frame projectionaccording to an aspect of this disclosure.

FIG. 28 is a perspective view of an elastic introducer frame accordingto an aspect of this disclosure.

FIG. 29 is a top view of an elastic introducer frame according to anaspect of this disclosure.

FIG. 30 a is a side view of an elastic introducer frame according to anaspect of this disclosure.

FIG. 30 b is a side view of an elastic introducer frame according to anaspect of this disclosure.

FIG. 31 is a perspective view of an elastic introducer frame accordingto an aspect of this disclosure.

FIG. 32 is a perspective view of an elastic introducer frame accordingto an aspect of this disclosure.

FIG. 33 is a perspective view of an elastic introducer frame accordingto an aspect of this disclosure.

FIG. 34 is a perspective view of an elastic introducer frame accordingto an aspect of this disclosure.

FIG. 35 is a perspective view of an elastic introducer frame accordingto an aspect of this disclosure.

FIG. 36 is a sectional view of an elastic introducer according to anaspect of this disclosure.

FIG. 37 is a perspective view of an elastic introducer frame accordingto an aspect of this disclosure.

FIG. 38 is a sectional view of an elastic introducer according to anaspect of this disclosure.

FIG. 39 is a sectional view of an elastic introducer according to anaspect of this disclosure.

FIG. 40 is a sectional view of an elastic introducer according to anaspect of this disclosure.

FIG. 41 is a sectional view of an elastic introducer according to anaspect of this disclosure.

FIG. 42 is a top view of an elastic introducer according to an aspect ofthis disclosure.

FIG. 43 is a top view of an elastic introducer system according to anaspect of this disclosure.

FIG. 44 is a top view of an elastic introducer system according to anaspect of this disclosure.

FIG. 45 is a perspective view of a dilator according to an aspect ofthis disclosure.

FIG. 46 is a perspective view of a dilator according to an aspect ofthis disclosure.

FIG. 47 is a partial sectional view of an elastic introducer systemaccording to an aspect of this disclosure.

FIG. 48 is a top view of an elastic introducer system according to anaspect of this disclosure.

FIG. 49 is a top view of an elastic introducer system according to anaspect of this disclosure.

FIG. 50 is a partial sectional view of an elastic introducer systemaccording to an aspect of this disclosure.

FIG. 51 is a partial sectional view of an elastic introducer systemaccording to an aspect of this disclosure.

FIG. 52 is a partial sectional view of an elastic introducer systemaccording to an aspect of this disclosure.

DETAILED DESCRIPTION

The following detailed description of an elastic surgical access devicerefers to the accompanying figures that illustrate exemplaryembodiments. Other embodiments are possible. Modifications can be madeto the embodiments described herein without departing from the spiritand scope of the present invention. Therefore, the following detaileddescription is not meant to be limiting.

Referring to FIGS. 1 and 14-17, introducer system 1 includes an elasticintroducer 10 that has a proximal end 12 and a distal end 14. Elasticintroducer 10 includes a wire structure 100, a liner 200, and a jacket300. In one aspect, wire structure 100 is laminated between liner 200and jacket 300. In an alternate aspect, wire structure 100 is embeddedwithin jacket 300. Wire structure 100 provides kink resistance forelastic introducer 10 and also allows elastic introducer 10 to activelyrecoil to a reduced diameter after passage of a transcatheter medicaldevice through a portion of elastic introducer 10. Elastic introducer 10includes a full diameter section 70 adjacent to hub 15 at proximal end12. In full diameter section 70, wire structure 100 is coiled. In fulldiameter section 70, jacket 200 and liner 300 are circumferentiallycontinuous and concentric with coiled wire structure 101. Elasticintroducer 10 also includes an expandable transition section 80 and anexpandable section 90. Expandable transition section 80 tapers thediameter of elastic introducer 10 from full diameter section 70 toexpandable section 90. In expandable transition section 80 andexpandable section 90, wire structure 100 is bent around a longitudinalaxis into a C-shaped wire structure 103 forming a series ofnon-continuous circumferential loops. In one aspect, jacket 300 andC-shaped wire structure 103 are not circumferentially continuous inexpandable transition section 80 and expandable section 90 and include alongitudinal gap visible in an expanded configuration. Expandabletransition section 80 facilitates a smooth transition from hub 15 andfull diameter section 70 to expandable section 90.

Typically, elastic introducer 10 is inserted into a vessel, such as thefemoral artery, passing through the skin of a patient, such that thedistal end 14 of elastic introducer 10 is inserted into the vessel. Inone aspect, elastic introducer 10 includes a tapered tip for insertionthrough the vessel wall without roll back of the tip. Elastic introducer10 can also include a suture eyelet for suture attachment to tissue. Ina further aspect, elastic introducer 10 can be used with a guide wire.In one aspect, elastic introducer 10 can be compatible with a 0.035 inchguide wire.

In one aspect, liner 200 is circumferentially continuous and forms alumen 20. In this aspect, wire structure 100 and jacket 300 are notcircumferentially continuous and include a longitudinal gap visible inan expanded configuration. As shown in FIGS. 1 and 16-17, in a collapsedconfiguration, elastic introducer 10 includes a liner overlap region 210and a jacket overlap region 310 in expandable transition section 80 andexpandable section 90. Liner overlap region 210 includes liner gapportion 240 defined by an inner fold 220 and an outer fold 230 of liner200. Liner gap portion 240 can be at least partially covered by jacket300. In one aspect, liner 200 extends around inner edge 320 to forminner fold 220. Jacket overlap region 310 is defined by inner edge 320and outer edge 330 of jacket 300. In an expanded configuration, inneredge 320 and outer edge 330 are separated longitudinally to form ajacket gap 340 (FIG. 9). In such a configuration, inner fold 220 andouter fold 230 are flattened to allow liner gap portion 240 to extendacross jacket gap 340.

In one aspect, liner 200 is tetrafluoroethylene (TFE). In alternateaspects, liner 200 can be Teflon®, polytetrafluoroethylene (PTFE),polyethylene, polyethylene terephthalate (PET), or polyester. Liner 200can have a low coefficient of friction on its inner surface tofacilitate advancement of a transcatheter medical device through theelastic introducer 10.

In one aspect, jacket 300 is polyurethane (e.g. Pellethane®, Elasthane™,Texin®, or Tecothane®) and can include 20% barium sulfate added as aradipacifier. In alternate aspects, jacket 300 can be a polyamidepolyether block copolymer such as Pebax®, nylon 12, or polyethylene. Thematerial for jacket 300 can also be loaded with tungsten or bismuthsubcarbonate to add radiopacity so that elastic introducer 10 can beradio detectable (radiopaque).

Wire structure 100 can be nickel titanium, Nitinol, with the diameter ofthe wire ranging from approximately 0.005 inches to approximately 0.02inches. In alternate aspects, wire structure 100 can benickel-cobalt-chromium-molybdenum (MP35N), stainless steel, high springtemper steel, or any other metal or composite having elastic propertiesto permit extension and recoil of elastic introducer 10.

Referring now to FIGS. 2-4, wire structure 100 includes a repeatinglongitudinal pattern and is shown in a flat or uncurved state. Forexample, wire structure 100 can include a sinusoid pattern 150 (FIG. 2),a square pattern 160 (FIG. 3), or a modified square pattern 170including a spine 176 (FIG. 4). Sinusoid pattern 150 includes a seriesof alternating adjacent straight portions 102 a and 102 b. Each straightportion 102 a is joined to a first adjacent straight portion 102 b by afirst bent end portion 104 a and to a second adjacent straight portion102 b by a second bent end portion 104 b. Conversely, each straightportion 102 b is joined to two straight portions 102 a by first bent endportion 104 a and second bent end portion 104 b.

Square pattern 160 includes a series of alternating adjacent straightportions 162 a and 162 b. Each straight portion 162 a is joined to afirst adjacent straight portion 162 b by a first end portion 164 a andto a second adjacent straight portion 162 b by a second end portion 164b. Conversely, each straight portion 162 b is joined to two straightportions 162 a by first end portion 164 a and second end portion 164 b.

Modified square pattern 170 includes a series of alternating adjacentstraight portions 172 a and 172 b. Each straight portion 172 a is joinedto a first adjacent straight portion 172 b by a first end portion 174 aand to a second adjacent straight portion 172 b by a second end portion174 b. Conversely, each straight portion 172 b is joined to two straightportions 172 a by first end portion 174 a and second end portion 174 b.Spine 176 extends along end portions 174 b. Spine 176 adds additionaltensile rigidity to wire structure 100. In a further aspect, endportions 174 b adjacent spine 176 can be welded or otherwise fixed tospine 176.

The below discussion refers to sinusoidal portion 150 of wire structure100, however square pattern 160 or modified square pattern 170 couldalso be used for wire structure 100.

Referring now to FIGS. 5-6, along the length of elastic introducer 10,the straight portions of wire structure 100 are curved aboutlongitudinal axis 30 into a C-shaped wire structure 103 forming a seriesof non-continuous circumferential loops. To form the non-continuouscircumferential loops, a first loop portion 112 of straight portions 102a and 102 b joined by first bent end portion 104 a is curved in a firstradial direction 110. A second loop portion 122 of straight portions 102a and 102 b joined by second bent end portion 104 b is curved in asecond radial direction 120. First loop portions 112 and second loopportions 122 form a series of alternating non-continuous circumferentialloops extending along longitudinal axis 30. In one aspect, in acollapsed configuration of elastic introducer 10, first loop portions112 and second loop portions 122 overlap longitudinally as demonstratedby wire overlap region 114. In one aspect, when elastic introducer 10 isin a collapsed configuration, first loop portions 112 are positionedwithin second loop portions 122 in wire overlap region 114 such that thesecond loop portions 122 cover the first loop portions 112. In analternate aspect, when elastic introducer 10 is in a collapsedconfiguration, first loop portions 112 and second loop portions 122 donot overlap and do not include a wire overlap region 114.

Referring now to FIG. 7, elastic introducer 10 is shown in a collapsedconfiguration where wire structure 100 does not include a wire overlapregion 114. In this aspect, second loop portions 122 extend slightlybeyond inner fold 220 and inner edge 320.

Referring now to FIGS. 8-14, elastic introducer 10 is designed to allowfor local expansion and subsequent recoil to reduce trauma to apatient's vessel. While introducing a transcatheter device, elasticintroducer 10 can transition from a collapsed state 40 prior toaccommodating transcatheter device 400, an expanded state 50 toaccommodate transcatheter device 400, and a reduced state 60 afterpassage of transcatheter device 400. The diameter of elastic introducer10 increases in expanded state 50 to accommodate transcatheter device400. This increase in diameter is accomplished by first loop portions112 and second loop portions 122 of wire structure 100 and inner edge320 and outer edge 330 of jacket 300 diverging circumferentially toincrease the effective diameter of elastic introducer 10. As elasticintroducer 10 increases in diameter, inner fold 220 and outer fold 230are flattened to allow liner gap portion 240 to span across jacket gap340. Thus, liner gap portion 240 extends across jacket gap 340 andmaintains a circumferentially continuous structure.

Arrow 410 shows the direction of travel of transcatheter device 400through elastic introducer 10. Expanded state 50 of elastic introducer10 is limited to the portion of elastic introducer 10 that surroundstranscatheter device 400. As transcatheter device 400 is moved distallyin the direction of arrow 410, distal portions of elastic introducer 10transition to expanded state 50 to accommodate transcatheter device 400.Furthermore, proximal portions of elastic introducer 10 transition toreduced state 60 following passage of transcatheter device 400.

After passage of transcatheter device 400, elastic introducer 10 recoilsand reduces in diameter to reduced state 60, proximal to transcatheterdevice 400. The recoil and reduction in diameter is accomplished by theelasticity of wire structure 100. The elasticity of wire structure 100allows first loop portions 112 and second loop portions 122 of wirestructure 100 and inner edge 320 and outer edge 330 of jacket 300 toconverge circumferentially and to reduce the effective diameter ofelastic introducer 10. As elastic introducer 10 reduces in diameter,inner fold 220 and outer fold 230 are again utilized to allow outer edge330 to partially cover the liner gap portion 240.

In one aspect, the diameter of elastic introducer 10 in the reducedstate 60 is equal to the diameter of elastic introducer 10 in thecollapsed state 40. In an alternate aspect, the diameter of elasticintroducer 10 in the reduced state 60 is greater than the diameter ofelastic introducer 10 in the collapsed state 40. In one aspect, elasticintroducer 10 expands from a diameter of approximately 15 FR toapproximately 19 FR. In an alternate aspect, elastic introducer 10expands from a diameter of approximately 13 FR to approximately 18 FR.

In one aspect, elastic introducer 10 can be sized for a transcatheterheart valve procedure and can be used with a transcatheter heart valvesand delivery system such as those described in U.S. Pat. No. 8,414,645;and U.S. Patent Publication Nos. 2006/0265056, 2007/0239266,2007/0239269, and 2011/0251681, which are incorporated herein byreference in their entirety. For example, transcatheter device 400 canbe an aortic valve prosthesis.

In alternate aspects, elastic introducer 10 can be sized for endoscopicprocedures, procedures in the coronary vessels, or procedures in theperipheral vessels.

Introducer system 1 is shown in FIG. 15. Introducer system 1 includeselastic introducer 10, a proximal end 12, a dilator 402, a flush tube404, a proximal hub including a valve 16, and a Luer connector orstopcock 18. In one aspect, dilator 402 is 14.5 FR. In another aspect,proximal end 12 is non-expandable.

Referring to FIGS. 18-19, elastic introducer 1010 has a proximal end1012 and a distal end 1014. All of the features discussed above withrespect to introducer system 1 and elastic introducer 10 areincorporated into the following description of elastic introducer 1010and introducer system 1001. Like reference numbers indicate identical orfunctionally similar elements. Elastic introducer 1010 includes anelastic frame 1100, a liner 1200, and a jacket 1300. In one aspect,liner 1200 is circumferentially continuous and forms a lumen 1020. Inthis aspect, elastic frame 1100 and jacket 1300 are notcircumferentially continuous and include a longitudinal gap visible inan expanded configuration. In a collapsed configuration, elasticintroducer 1010 includes a liner overlap region 1210 and a jacketoverlap region 1310. Liner overlap region 1210 includes liner gapportion 1240 defined by an inner fold 1220 and an outer fold 1230 ofliner 1200. Liner gap portion 1240 can be at least partially covered byjacket 1300. In one aspect, liner 1200 extends around inner edge 1320 toform inner fold 1220. Jacket overlap region 1310 is defined by inneredge 1320 and outer edge 1330 of jacket 1300. In an expandedconfiguration, inner edge 1320 and outer edge 1330 are separatedlongitudinally to form a jacket gap 1340 (FIG. 36). In such aconfiguration, inner fold 1220 and outer fold 1230 are flattened toallow liner gap portion 1240 to extend across jacket gap 1340.

In one aspect, elastic frame 1100 is laminated between liner 1200 andjacket 1300. In an alternate aspect, elastic frame 1100 is embeddedwithin jacket 1300. Elastic frame 1100 provides kink resistance forelastic introducer 1010 and also allows elastic introducer 1010 toactively recoil to a reduced diameter after passage of a transcathetermedical device through a portion of elastic introducer 1010.

FIGS. 18-39 show embodiments of elastic frame 1100. In one aspect,elastic frame 1100 includes spine 1102 and one or more projections 1104connected along spine 1102. As shown, for example, in FIG. 20, elasticframe 1100, or portions thereof, can be stamped, etched, and/or cut froma flat sheet of material using techniques that are known in the art.Flat elastic frame 1100 can then be rolled, shaped, and heat set to forma tubular structure for use within elastic introducer 1010. If elasticframe 1100 is cut from a flat sheet of material, elastic frame 1100 mayhave a flattened or rectangular cross-section, however other shapesand/or cross-sections are acceptable. In another aspect, elastic frame1100, or portions thereof, can be cut and/or etched from a tube ofmaterial using techniques that are known in the art. For example,elastic frame 1100 may be laser cut from a piece of material. Elasticframe 1100 may be cut or formed from a single piece of material or maybe assembled from a number of different components and/or materials. Forexample, elastic frame 1100 may comprise nickel titanium, Nitinol,nickel-cobalt-chromium-molybdenum (MP35N), stainless steel, high springtemper steel, and/or any other metal or composite having elasticproperties to permit extension and recoil of elastic introducer 10. Inone aspect, following cutting, elastic frame 1100 may be processedfurther, for example, removal of sharp edges or burrs, wall thicknessreduction, etc., which may be accomplished via filing, micro-blasting,acid-etching, electro-polishing, etc.

Spine 1102 provides axial stiffness along elastic introducer 1010.Projections 1104 permit bending of elastic introducer 1010 as it ispassed through a patient's vasculature. Projections 1104 arenon-circumferentially continuous and thus allow elastic introducer 1010to locally expand to an expanded diameter to accommodate passage of atranscatheter medical device through elastic introducer 1010.Projections 1104 also maintain a radial force inward towards the centerof elastic introducer 1010 so that elastic introducer 1010 can activelyrecoil to a reduced diameter after passage of the transcatheter medicaldevice.

Projections 1104 can extend from one or both edges of spine 1102. Asshown in FIGS. 19 and 21, projections 1104 are curved about longitudinalaxis 30 into a C-shape in a first radial direction 110 or a secondradial direction 120. In a collapsed configuration, a portion of jacket1300 overlaps in jacket overlap region 1310. In one aspect, theprojections 1104 do not extend circumferentially into jacket overlapregion 1310. In another aspect, projections 1104 extend into jacketoverlap region 1310. In this aspect, when elastic introducer 1010 is ina collapsed configuration, projections 1104 extending in first radialdirection 110 are positioned radially beneath the projections 1104extending in second radial direction 120 within jacket overlap region1310.

The number, shape, and pattern of projections 1104 can affect expansionstress, flexibility, and bending compliance of elastic introducer 1010.FIGS. 19-33 show some of the possible patterns. As shown in FIGS. 20-21,a projection 1104 extending in first radial direction 110 and anopposing projection 1104 extending in second radial direction 120 canextend from the same axial location on spine 1102. In anotherembodiment, projections 1104 a extending from opposite edges of spine1102 b can be offset. For example, a projection 1104 a extending infirst radial direction 110 and an opposing projection 1104 a extendingin second radial direction 120 can extend from different axial locationson spine 1102 b. The offset of projections 1104 a permits a smallerprofile for elastic introducer 1010. In another aspect, projections 1104b can include a curved circular portion at one end. In a furtherembodiment, projections 1104 c can be arched along spine 1102 c. Asshown in FIG. 31, all projections 1104 g can extend from a single sideof spine 1102 g.

As shown in FIG. 26, the thickness of a portion of projection 1104 d canbe modified so that projection 1104 d is tapered in the radialdirection. For example, projection 1104 d can have a tip end 1130 with atip end thickness 1132 and a spine end 1140 with a spine end thickness1142. In one aspect, spine end thickness 1142 is greater than tip endthickness 1132, providing projection 1104 d with a tapered profile. Thetapered profile of projection 1104 d permits an overall lower profile ofelastic introducer 1010. In one embodiment, the size of spine endthickness 1142 and tip end thickness 1132 can each range fromapproximately 0.005 inches to approximately 0.015 inches.

In another embodiment shown in FIG. 27, the width of a portion ofprojection 1104 d can be modified so that projection 1104 d can betapered in the axial direction. For example, projection strut 1106 onprojection 1104 d can have a spine end width 1144 and a tip end width1134. In one aspect, spine end width 1144 is greater than tip end width1134. In one embodiment, the size of spine end width 1144 and tip endwidth 1134 can each range from approximately 0.005 inches toapproximately 0.030 inches.

Referring now to FIGS. 28-30 b, elastic frame 1100 e can incorporatehook projections 1105 e with eye projections 1104 e to limit the maximumexpansion of elastic frame 1100 e and elastic introducer 1010. Whenformed in a tubular structure, each hook projection 1105 e can engagewith a respective eye projection 1104 e to limit the expansion ofelastic frame 1100 e to expansion distance 1150. In one embodiment,expansion distance 1150 can range from approximately 10 French toapproximately 22 French.

Referring now to FIGS. 32-33, elastic frame 1100 j can include one ormore segmented projections 1104 j spaced along common axis 1108 j.Segmented projections 1104 j are not joined by a common spine, butrather are connected through liner 1200 and/or jacket 1300 on elasticintroducer 1010. Portions of each segmented projection are curved aboutlongitudinal axis 30 into a C-shape in a first radial direction 110 or asecond radial direction 120.

The axial spacing of projections 1104 along spine 1102 can be modifiedto alter the bending compliance and flexibility of elastic introducer1010. For example, the axial spacing of projections 1104 along spine1102 can be increased in areas of elastic introducer 1010 whereadditional flexibility is required. In one embodiment, the axial spacingbetween adjacent projections 1104 can range from approximately 1 mm toapproximately 10 mm.

Referring now to FIG. 34, elastic frame 1100 f can be a stent-like lasercut tube having a plurality of diamond shaped cells that permit localexpansion of elastic introducer 1010. In a further aspect, the shape ofthe cells and the stiffness of elastic frame 1100 f can be modifiedalong the length of elastic frame 1100 f. In one aspect, elastic frame1100 f can have a proximal rigid portion designed to resist bending, acompliant mid-section designed to bend with and conform to a patient'sanatomy, and a distal rigid portion designed to aid in valve retrieval.

In another embodiment, the elastic frame 1100 can be positioned across afold or gap in elastic introducer 1010 to close jacket gap 1340. Byreducing the amount of material used for elastic frame 1100, the designprofile of elastic introducer 1010 can be minimized. As shown in FIGS.35-36, elastic frame 1100 h can have a continuous lace pattern acrossjacket gap 1340. Elastic frame 1100 h includes an edge portion 1103 hand a gap portion 1105 h. Respective edge portions 1103 h are anchoredto inner edge 1320 and outer edge 1330 of jacket 1300 to provide aclosing mechanism across jacket gap 1340. In another embodiment, elasticintroducer 1010 can include one or more elastic frames 1100 i axiallyspaced across jacket gap 1340. Elastic frames 1100 i are distinctsegments and are connected only through liner 1200 and/or jacket 1300 onelastic introducer 1010. Elastic frames 1100 i can have an “N” or “Z”shape to permit expansion of introducer 1010. During expansion, elasticframes 1100 i can straighten across jacket gap 1340 to locally increasethe diameter of elastic introducer 1010. In one aspect, elastic frames1100 i can be laminated between liner 1200 and jacket 1300.

In one aspect shown in FIGS. 38-39, elastic introducer 1010 can includemultiple longitudinal gaps 1340 a and 1340 b. In this aspect, jacket1300 can include at least two longitudinal gaps visible in an expandedconfiguration. In a collapsed configuration, elastic introducer 1010includes two liner overlap regions 1210 a, 1210 b, and two jacketoverlap regions 1310 a, 1310 b. Liner overlap regions 1210 a, 1210 b,include liner gap portions 1240 a, 1240 b, respectively defined by innerfolds 1220 a, 1220 b, and outer folds 1230 a, 1230 b of liner 1200.Liner gap portions 1240 a, 1240 b, can be at least partially covered byjacket 1300. In one aspect, liner 1200 extends around inner edges 1320a, 1320 b, to form inner folds 1220 a, 1220 b. Jacket overlap regions1310 a, 1310 b, are defined by inner edges 1320 a, 1320 b and outeredges 1330 a, 1330 b of jacket 1300, respectively. In an expandedconfiguration, inner edges 1320 a, 1320 b, are separated longitudinallyfrom outer edges 1330 a, 1330 b to form jacket gaps 1340 a, 1340 b. Inthe expanded configuration, inner folds 1220 a, 1220 b, and outer folds1230 a, 1230 b are flattened to allow liner gap portions 1240 a, 1240 bto extend across jacket gaps 1340 a, 1340 b, respectively. In oneaspect, each longitudinal gap 1340 a and 1340 b can include an elasticframe positioned across the gap, such as is discussed above with respectto FIGS. 35-36.

Because distal end 1014 of elastic introducer 1010 is expandable, jacketgap 1340 can fish-mouth, or open when elastic introducer 1010 traversesa bend in a patient's vasculature. As a result, inner fold 1220 andouter fold 1230 can flip at distal end 1014 causing a twist in jacketoverlap region 1310. In addition, a user is required to twist elasticintroducer 1010 on entry into the patient's vasculature to preventopening of distal end 1014 from interaction with tissue.

Referring now to FIGS. 40-42, diameter retention bond 1408 can beutilized to retain distal end 1014 in a collapsed or closed state.Diameter retention bond 1408 prevents distal end 1014 from openingduring advancement of elastic introducer 1010 through the patient'svasculature. In one aspect, diameter retention bond 1408 seals andmaintains inner fold 1220 and outer fold 1230 at distal end 1014 ofelastic introducer 1010. Diameter retention bond 1408 can be positionedbetween jacket 1300 and liner gap portion 1240. In another aspect,diameter retention bond 1408 can be positioned between liner 1200 andliner gap portion 1240. In a further aspect, diameter retention bond1408 can be positioned on jacket 1300 across outer edge 1330 and outerfold 1230, for example as shown in FIG. 42.

In another embodiment, diameter retention pin 1406 can be utilized toretain distal end 1014 in a collapsed or closed state. Diameterretention pin 1406 can extend through a portion of jacket 1340 and liner1200 including liner gap portion 1240 and a portion of outer edge 1330and a portion inner edge 1320. In another aspect, diameter retention pin1406 can extend completely through liner gap portion 1240, outer edge1330, and inner edge 1320 to retain distal end 1014 in a collapsed orclosed state.

Diameter retention bond 1408 and diameter retention pin 1406 can bebreakable and dissolvable upon passage of transcatheter device 400.

Referring now to FIGS. 43-49, dilator 1402 can include a diameterretention element 1404 to protect distal tip 1014 of elastic introducer1010 and to retain distal end 1014 in a collapsed or closed state duringadvancement of elastic introducer 1010 through a patient's vasculature.During advancement, one or more diameter retention elements 1404 canextend around at least a portion of elastic introducer 1010 at distalend 1014. In one aspect, diameter retention element 1404 can extendacross outer edge 1330 and outer fold 1230. Diameter retention element1404 can be elastic and can collapse against dilator 1402 when dilator1402 and diameter retention element 1404 are advanced beyond distal end1014 of elastic introducer 1010. This allows dilator 1402 and diameterretention element 1404 to be pulled back through elastic introducer1010.

In another embodiment, dilator 1402 can include a plurality of diameterretention elements 1404 supporting an introducer cover material 1405.Introducer cover material 1405 can be a biocompatible material and cancover the entire distal end 1014 of elastic introducer 1010.

In another embodiment, a dilator 1402 can include a recess 1403 formedby diameter retention elements 1404. During insertion, distal end 1014of elastic introducer 1010 can be positioned within recessed 1403 ofdilator 1402. In this aspect, diameter retention element 1404 can bemovable by a retraction mechanism in hub 1015. The retraction mechanismcan pull diameter retention elements 1404 against the outer surface ofdilator 1402 to permit dilator 1402 and diameter retention elements 1404to be pulled back through elastic introducer 1010.

In a further embodiment, dilator 1402 can include a device deliverycapsule 1500 to retain a prosthetic device 1502. Diameter retentionelement 1404 can be positioned on delivery capsule 1500 and distal end1014 of elastic introducer can be positioned under diameter retentionelement 1404. In this aspect, elastic introducer 1010 can be used as aninline sheath to advance elastic introducer 1010 and prosthetic device1502 through a patient's vasculature. Introducers used as an inlinesheath are discussed in U.S. Patent Publication Nos. 2011/208296,2006/0206192, and U.S. application Ser. No. 13/914,802, which areincorporated herein by reference in their entirety. Diameter retentionelement 1404 can prevent distal end 1014 from opening and traveling overdelivery capsule 1500 during use as an inline sheath. In a furtheraspect, dilator 1402 can include a ramp 1410 axially positioned proximalto diameter retention element 1404. Ramp 1410 lifts the edge of distalend 1014 as it approaches diameter retention element 1404 when dilator1402 is passed back through elastic introducer 1010. Ramp 1410 can thusreduce the risk of diameter retention element 1404 snagging on distalend 1014.

Referring now to FIGS. 50-52, in one embodiment, dilator 1402 caninclude a rigid section 1420 to prevent flexion of dilator 1402 at thissection. Placing distal end 1014 of elastic introducer 1010 at rigidsection 1420 can help to maintain distal end 1014 in a collapsed orclosed state during advancement of elastic introducer 1010 through apatient's vasculature. Rigid section 1420 can be formed by placingadditional material in a band-like structure on dilator 1402 or by usinga higher durometer material in the region of rigid section 1420.

In another embodiment, dilator 1402 can include a proximal flexiblesection 1428 and/or a distal flexible section 1432 to induce bending ofdilator 1402 in these sections. Placing distal end 1014 of elasticintroducer 1010 in section 1430 at an axial location distal to proximalflexible section 1428 and proximal to distal flexible section 1432 canhelp to maintain distal end 1014 in a collapsed or closed state duringadvancement of elastic introducer 1010 through a patient's vasculature.Proximal flexible section 1428 and distal flexible section 1432 can beformed by using a lower durometer material in the region of therespective flexible sections.

In another embodiment, dilator 1420 can include one or more cuts 1440around the outer surface of the dilator 1402 in the region of proximalflexible section 1441. And, dilator 1420 can include one or more cuts1442 around the outer surface of dilator 1402 in the region of distalflexible section 1443. As with proximal flexible section 1428 and distalflexible section 1432, proximal flexible section 1441 and distalflexible section 1443 induce bending of dilator 1402 in these sections.Placing distal end 1014 of elastic introducer 1010 in a section at anaxial location distal to proximal flexible section 1441 and proximal todistal flexible section 1443 can help to maintain distal end 1014 in acollapsed or closed state during advancement of elastic introducer 1010through a patient's vasculature.

The foregoing description has been presented for purposes ofillustration and enablement, and is not intended to be exhaustive or tolimit the invention to the precise form disclosed. Other modificationsand variations are possible in light of the above teachings. Theembodiments and examples were chosen and described in order to bestexplain the principles of the invention and its practical applicationand to thereby enable others skilled in the art to best utilize theinvention in various embodiments and various modifications as are suitedto the particular use contemplated. It is intended that the appendedclaims be construed to include other alternative embodiments of theinvention.

What is claimed is:
 1. A surgical access system comprising: anintroducer having an interior lumen, the lumen being configured toexpand from a first diameter to a second diameter, the introducerincluding: an elastic frame, and a diameter retention element positionedat a distal end of the introducer to retain the distal end of theintroducer at the first diameter.
 2. The surgical access system of claim1, wherein the retention element is a pin to fuse the distal end of theintroducer.
 3. The surgical access system of claim 1, the introducerfurther comprising a circumferentially continuous biocompatible materiallayer including a fold at the first diameter, wherein the retentionelement is a bond between adjacent portions of the circumferentiallycontinuous biocompatible material in the fold.
 4. The surgical accesssystem of claim 1, the introducer further comprising anon-circumferentially continuous biocompatible material layer includinga first circumferential edge portion and a second circumferential edgeportion such that the first circumferential edge portion extends overthe second circumferential edge at the first diameter, wherein theretention element is a bond between the first circumferential edgeportion and the second circumferential edge portion.
 5. The surgicalaccess system of claim 1, the introducer further comprising anon-circumferentially continuous biocompatible material layer includinga first circumferential edge and a second circumferential edge such thata longitudinal slit extends along the first circumferential edge in thefirst diameter and a longitudinal gap extends between the firstcircumferential edge and the second circumferential edge at the seconddiameter, wherein the retention element extends across the longitudinalslit at the distal end of the introducer.
 6. A surgical access systemcomprising: an introducer having an elastic frame and an interior lumen,the lumen being configured to expand from a first diameter to a seconddiameter; and a dilator slidably disposed about the interior lumen, thedilator including: a distal tip having an outer diameter greater thanthe first diameter, and a diameter retention element positioned at aproximal end of the tip to retain a distal end of the introducer at thefirst diameter.
 7. The surgical access system of claim 6, wherein theretention element surrounds the distal end of the introducer.
 8. Thesurgical access system of claim 6, wherein the retention element iselastic.
 9. The surgical access system of claim 6, the retention elementfurther comprising a first elastic member and a second elastic member.10. The surgical access system of claim 9, the retention element furthercomprising a biocompatible material extending between the first elasticmember and the second elastic member to surround a portion of the distalend of the introducer.
 11. The surgical access system of claim 6,wherein a diameter of the proximal end of the tip is reduced toaccommodate the retention element.
 12. The surgical access system ofclaim 6, wherein the distal tip of the dilator includes a devicedelivery capsule.
 13. The surgical access system of claim 12, whereinthe retention element extends from a proximal end of the device deliverycapsule and surrounds a portion of the distal end of the introducer. 14.The surgical access system of claim 13, wherein the retention element iselastic.
 15. The surgical access system of claim 13, further comprisingan inclined element on a portion of the dilator proximal to theretention element.
 16. The surgical access system of claim 13, whereinthe retention element is movable from a first radial position to asecond radial position.
 17. The surgical access system of claim 12,wherein the retention element is a proximal edge of the device deliverycapsule.
 18. A surgical access system comprising: an introducer havingan elastic frame and an interior lumen, the lumen being configured toexpand from a first diameter to a second diameter; and a dilatorslidably disposed about the interior lumen, the dilator having a firstportion having a first axial stiffness and a second portion distal tothe first portion, the second portion having a second axial stiffnesssuch that the dilator is configured to bend at the second portion. 19.The surgical access system of claim 18, wherein the distal end of theintroducer is positioned at the first portion in a deliveryconfiguration.
 20. The surgical access system of claim 19, wherein thesecond portion includes a circumferential groove.